Motor Drive Vibration Spectrum Detection for Member Deterioration
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Solution Overview
Problem
Existing methods, such as those described in Patent Literature 1, cannot determine deterioration in specific members of an electric motor, like a rotor, stator, or shaft, nor can they assess deterioration in vibratory members, like a bogie, which affects the reliability of railway vehicle operation.
Innovation Solution
A drive apparatus comprising a power circuit that outputs a current with specific frequency components matching the natural frequencies of the electric motor's members or vibratory members, and a deterioration determining device that uses frequency domain data from vibration sensors to identify any deterioration based on the frequency spectrum values at these natural frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If frequency analysis is performed on ground leakage current to determine motor abnormality, then abnormality detection capability is improved, but the ability to determine deterioration in specific members (rotor, stator, shaft) and vibratory members (bogie) deteriorates
Solution Approach 1:
The patent segments the vibration analysis by frequency components, separating vibrations at the natural frequency of motor members (2fs, 3fs, 4fs) from vibrations at the natural frequency of the bogie. This frequency-based segmentation allows independent determination of deterioration in specific members, resolving the information loss problem while maintaining abnormality detection capability.
Solution Approach 2:
The patent introduces vibration signals as an intermediary measurement medium. By measuring vibrations at specific frequencies and comparing them to reference values, the system can indirectly determine deterioration in specific members without directly observing the deterioration, thus preserving detailed diagnostic information.
2Reliability
If general vibration monitoring is performed to detect motor abnormalities, then overall system reliability monitoring is improved, but the precision of determining deterioration in individual members deteriorates
Solution Approach 1:
The patent divides the vibration spectrum into distinct frequency bands corresponding to different members (motor members at 2fs, 3fs, 4fs and bogie at its natural frequency). This segmentation enables simultaneous monitoring of overall reliability through comprehensive vibration analysis while maintaining precise member-specific diagnosis through frequency-selective measurement.
Solution Approach 2:
The patent applies local quality analysis by assigning different evaluation criteria to different frequency components. Each member's deterioration is evaluated based on its characteristic frequency signature, allowing precise local diagnosis while contributing to overall system reliability assessment.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The drive apparatus effectively determines deterioration in the members of the electric motor and vibratory members by analyzing the frequency spectrum, thereby ensuring reliable operation of railway vehicles without affecting the electric motor's performance.
Implementation Method 1
a sensor signal output by a vibration sensor to measure a magnitude of vibration of the load or the vibratory member
Implementation Method 2
generates frequency domain data indicating a magnitude of vibration of the load or the vibratory member for each frequency based on a sensor signal output by a vibration sensor
Implementation Method 3
vibration resulting from an electromagnetic excitation force generated in the load
Data Source
AI summary
A drive apparatus includes a power circuit and a deterioration determining device. The power circuit outputs, to a load, a current including a current component having a frequency determined by a natural frequency of at least one member of the load or a vibratory member to vibrate when receiving vibration resulting from an electromagnetic excitation force generated in the load or by a value of a natural number multiple of a rotation frequency of a rotator that is one of the at least one member. The deterioration determining device generates frequency domain data based on a sensor signal output by a vibration sensor and determines deterioration of the at least one member of the load or the vibratory member based on a value of a frequency spectrum indicated by the frequency domain data at the natural frequency or the rotation frequency used to determine the frequency of the current component.